Recommendations?

these are well known so maybe you have already read them but just in case: http://www.mangago.zone/read-manga/black_knight/
http://www.mangago.zone/read-manga/black_sun/
There is also this one
http://www.mangago.zone/read-manga/love_story_nishida_higashi/

or this http://www.mangago.zone/read-manga/kouya_no_seifukuou/